Machines for removing fins from spirally finned heat exchange tubes



Se t. 18, 1962 R. M. STIKELEATHER 3,054,313

MACHINES FOR REMOVING F FINNED HEAT EXCHANGE TUBES Filed Dec. 25, 1958 INS FROM SPIRALLY 5 Sheets-Sheet 1 B E E E wZEDQZ $222K $383M vm. um.

Sept. 18, 1962 3,054,313

R. M. STIKELEATHER MACHINES FOR REMOVING FINS FROM SPIRALLY FINNED HEAT EXCHANGE TUBES Filed D90. 23, 1958 5 Sheets-Sheet 2 :3 g I I 1 M L? 13 E i 1 5 J ilt? Q I: 1T

m 5] l i Sept. 18, 1962 R. M. STIKELEATHER 3,054,313

MACHINES FOR REMOVING FINS FROM SPIRALLY FINNED HEAT EXCHANGE TUBES 5 Sheets-Sheet 3 Filed Dec. 23, 1958 Sept. 18, 1962 M. STIKELEATHER 3,054,313

MACHINES FOR REMOVING FINS FROM SPIRALLY FINNED HEAT EXCHANGE TUBES Filed Dec. 23, 1958 5 Sheets-Sheet 4 Sept. 18, 1962 R. M. STIKELEATHER MACHINES FOR REMOVING F INS FROM SPIRALLY FINNED HEAT EXCHANGE TUBES 5 Sheets-Sheet 5 Filed Dec. 2s 1958 3,954,313 Patented Sept. 18, 1962 3,054,313 MACHINES FOR REMOVING FINS FROM SPI- RALLY FINNED HEAT EXCHANGE TUBES Robert M. Stilteleather, Holbroolt, Mass, assignor to Aerofin Corporation, Syracuse, N.Y., a corporation of New Jersey Filed Dec. 23, 1958, Ser. No. 782,506 Claims. (Cl. 82-40) This invention relates to the manufacture of finned tubing, and relates more particularly to machines for preparing cut-ofii lengths of finned tubing for assembly in heat exchangers.

This application is a continuation-in-part of my copending application, Serial No. 560,682 which Was filed on January 21, 1956, and which will issue as Patent No. 2,866,257 on December 30, 1958. In said application, there is disclosed a machine for cutting off predetermined lengths of rotating finned tubing as it emerges from a finning machine. The present invention provides a machine synchronized with the machine of said application, for receiving a length of finned tubing as it is cutoif, and preparing it for assembly in a heat exchanger by removing the fins at the ends of the tube, and intermediate its ends to provide clearance for tube supports; by removing burrs at one end of the tube, and by spinning the other end of the tube to close it.

An object of this invention is to prepare lengths of finned tubes for assembly in heat exchangers.

Another object of this invention is to remove fins from lengths of finned tubes without damaging the remaining fins.

Another object of this invention is to close an open end of a finned tube while fins are being removed from the tube.

Another object of this invention is to remove burrs from an end of a finned tube while fins are being removed from the tube.

This invention will now be described with reference to the annexed drawings, of which:

FIG. 1 is a side view of a cut-off machine with controls for operating the machine of this invention;

FIG. 2 is a side view of one embodiment of this invention shown below the cut-off saw of FIG. 1;

FIG. 3 is a compressed air piping diagram showing the cam operated air valves of FIG. 1, and the compressed air cylinders of FIG. 2;

FIG. 4 is an enlarged side view of the mechanisms for working on the ends of the tubes, such mechanisms being shown in section;

FIG. 5 is an enlarged top plan view, partially in section, of the mechanism for clamping and rotating a cutofi length of finned tube;

FIG. 6 is an end view on a reduced scale of the clamping mechanism of FIG. 5 clamped around a finned tube;

FIG. 7 is a section on the same scale as FIG. 6, along the line 77 of FIG. 5, with the finned tube shown as being ejected from the clamping mechanism;

FIG. 8 is a section on the same scale as FIG. 7, along the line 88 of FIG. 5, and shows the clamping mechanism open for receiving a finned tube; and

FIG. 9 is an end view of the saw mechanism for removing fins from intermediate the ends of a finned tube. FIG. 10 is a view similar to FIG. 6, greatly enlarged, and

FIG. 11 is a view similar to FIG. 7, greatly enlarged, and with other portions shown in section and in dashed line outline.

A conventional finning machine It] delivers rotating finned tubing 11 to the cut-off mechanism of FIG. 1, which consists of a plate 12 having journalled thereto a threaded shaft 13 driven by belt 14 and pulleys 15 from the finning machine 10. An air cylinder 16 attached to the plate 12 has a half-nut 17 on the upper end of its piston rod, the half-nut being adapted to be moved against the threaded portion of the shaft 13 for causing the plate 12 to move in the direction of longitudinal movement of the finned tubing advancing from the finning machine.

A gear box 20 is driven from the shaft 13 by belt 21 and pulleys 22, and rotates through a slippable clutch 24, a cam cylinder 26 which has cams S1, S2, S3, S4, S5, S6 and S7 which contact cam followers on valves V1, V2, V3, V4, V5, V6 and V7 respectively, which are connected between a source of compressed air which is not shown, and air cylinders C1, C2, C3, C4, C5, C6 and C7 respectively. The cylinders C1-C7 operate tongs T1-T7 respectively, which close around the finned tube when its advancing end leaves each tong.

As the plate 12 moves forwardly, a pivoted lug which it carries, opens valve V12 which admits compressed air into a cylinder 32 (FIG. 3) which has a piston rod 63 to which one end of chain 31 is attached, the other end of the chain being free. The chain is meshed with a sprocket on the cam cylinder 26. When the plate has moved a predetermined distance forwardly, the valve V12 is opened to cause the chain to be moved by the piston rod 63 to rotate the cylinder 26 back-wardly to restore it to its original position.

An electric motor 33 is attached to the plate 12, and has a saw 34 on its shaft for cutting the tube 11 when a predetermined length has emerged from the finning machine. A target disc 35 aligned with the axis of the tube 11, moves when the advancing end of the tube strikes it, a shaft 36 of support 37 which opens valve V13 which admits compressed air into the cylinder C13 which moves the support 37 and the shaft 36 and disc 35 away from the adjacent end of the tube. At the same time the valve V13 admits compressed air into the cylinder 16 to cause the half-nut 17 to engage the threaded portion of the shaft 13 to cause the plate 12 carrying the saw 34 to move forwardly. Not shown herein, but shown in said application is a control which causes the saw 34 to cut the tube 11 when the plate 12 has advanced a predetermined distance. When the tube has been cut off by the saw 34, the valve V12 is opened to cause the cylinder 32 to rotate through the chain 31, the cam cylinder 26 back-wardly, restoring it to its initial position. This opens the valves V1V7 causing the cylinders C1-C7 to open the tongs Tl-T7, permitting the cut-off tube to drop from the tongs.

The plate 12 continues to move forwardly until another lug it carries opens an air valve V14 which admits compressed air into the cylinder *16 to cause the latter to pull the half-nut 17 out of engagement with the threaded portion of the shaft v13. A spring 18 then pulls the plate 12 back to its initial position. At the same time, the valve V14 admits compressed air into the cylinder C13 to cause the latter to move the assembly of the target disc 35 to its initial position.

The construction described so far in connection with FIGS. 1 and 3 is that disclosed in said application. This invention adds the mechanism shown in the lower portion of FIG. 2, and the controls for operating such mechanism.

The cam cylinder 26 of FIG. 1 has the additional cam surfaces S8, S9, S10 and 811 which contact cam followers which open valves V8, V9, V10 and V11 respectively, after the cam cylinder 26 has been rotated back to its initial position to cause a cut-off tube to drop from the tongs. When a length of finned tube has been cut-off by the saw, it falls from the open tongs T1-T7, guided by guides 39, 4t and 41 into a clamp shown in open position by FIG. 8, consisting of a fixed clamp segment 42 and a movable clamp segment 43, both segments having inner surfaces formed as segments of a cylinder having a diameter equal to the outer diameter of the fins on the finned tube 11. The cut-off tube when it falls into the clamp is also supported on tables 44 and 65 atone side of the clamp.

The clamp has a frame 45 rotatably supportd on sleeve 46 which is journalled in base 47. The sleeve 46 has a pinion gear 48 therearound and attached thereto, and which is meshed with rack 49 attached to piston 50 of the air cylinder C10. A rotary shaft 51 extends through the sleeve 46 and has a pulley 52 thereon which is driven by belt 53 of electric motor 54. The shaft 51 has, as is shown more clearly by FIG. 4, a threaded inner end 56 of reduced diameter on which is threaded a sleeve 57 of a spinning head 58. The head 58 has a spinning tool 60 having a recess shaped as a portion of a sphere, and which when rotated by the motor 54, spins the adjacent open end of the cut-off tube 11 to close it as shown by FIG. 4. The head 58 also has a pair of diametrically opposite cutter tools 62 having cutting edges in alignment with the outer surface of the tube on which the fin is wound, and which, when rotated by the motor 54 cuts off the fin at that end of the tube. The outer end of the shaft 51 is attached to the piston rod of cylinder C11 which is adapted to move the head 58 forwardly, and to retract the head 58 as will be described later.

Aligned with the shaft 51 at the opposite end of a cutoff tube is an air cylinder C12 having a piston rod 66 the threaded inner end of which is formed as a grooved tool 67 having an outer diameter equal to the inner diameter of the cut-off tube, and which when revolved, removes burrs from the inner surface of the adjacent open end of the tube. A sleeve 108 is threaded onto the piston rod 66, and has clamped thereto, a pair of cutter tools 69 similar to the cutter tools 62, for cutting off the fin at that end of the tube. The outer end of the piston rod 66 is within and attached to a coupling 68 which is driven by an electric motor 80.

The cylinders C11 and C12 are connected to the compressed air source through valve V11 which is opened by a cam follower on cam surface S11 of the cam cylinder 26.

The movable clamp segment 43 of the tube clamp is pivoted at 70 to a link 71 which is rotatably attached to the lower end of piston rod 55 of air cylinder C8. Beyond the ends of the clamp segments 42 and 43 are tube ejecting fingers 72 which are attached to rod 73 which is journalled for rotation in frame members 74. A latch 75 is pivoted at one end to the movable clamp segment 43, and its other end is curved to fit against a curved pawl 76 attached through lever 77 to the rod 73 when the movable clamp segment 43 approaches its outermost position.

When the piston rod 55 is extended, the clamp segments 42 and 43 are closed about the cut off tube as shown by FIG. 6. When the piston rod 55 is retracted, the clamp segment 43 is rotated outwardly to permit the removal of the tube, and the rod 73 is rotated by the pressure of the curved outer end of the latch 75 against the pawl 76 to rotate the rod 73 to move the fingers 72 to eject the tube from the clamp as shown by FIG. 7, following which the ejected tube rolls over deflectors 78 on the fingers 72, and falls below the clamp. A coiled spring 79 around the rod 73 returns the rod 73 and the pawl 76 to their initial positions. The latch 75 has a portion 99 extending perpendicular thereto, and which rides over the pawl 76 when the clamp segment 43' reaches its extreme outward position, by which time the tube will have been ejected from the clamp.

The clamp segments 42 and 43 when closed about a finned tube 11 when the movable segment 43 has been moved to its innermost position, are, as shown by FIGS. 10 and 11, symmetrical about a common axis which is the rotary axis of the sleeve 46 to which the pinion gear 43 is attached, and which rotates the frame 45 about that axis.

The previously described cutter tools 62 and 69 are for removing fin from the end of a finned tube so that tube supports can be placed around the ends of a nest of tubes of a heat exchanger. When the tubes have substantial lengths, they need to be supported at one or more intermediate portions, requiring removal of fins from such portions. For accomplishing this, a sawing mechanism 80 is provided. It consists, as most clearly shown by FIG. 9, of a frame 81 having slidable thereon a base 82 having an upturned outer end 83 attached to piston rod 34 of air cylinder C9, and having an upturned inner end 88. An electric motor 85 is mounted on the base 82, and has a gear 86 on its shaft which is meshed with a gear 87 supported for rotation on top of the motor 85. The gears 86 and 87 have pulleys 89 and 90 respectively, attached thereto, and which rotate through belts 91 and 92 respectively, pulleys 93 and 94 respectively, attached to rotary saws 95 and 96 respectively. The pulleys 93 and 94 and the saws 95 and 96 are supported for rotation by the upturned inner end 88 of the base 82. Guides 98 are spaced apart a distance equal to the outer diameter of the fin on the finned tube 11, and the saws 95 and 96 are spaced apart a distance equal to the diameter of the tube on which the fin is wound. When the cylinder C9 is supplied with compressed air by the opening of the valve V9, it moves the base 82 and the saws 95 and 96 towards the cut-off tube held in the clamp, until the saws are opposite sides of the tube, the guides 98 positioning the cut-off tube which has some flexibility, between the saws. The saws 95 and 96 rotate in opposite directions. The clamped tube is rotated 360 by the cylinder C10, the rack 49 and gear 48, while the saws 95 and 96 are aligned with the tube, so that the fin on the tube is cut off by the saws 95 and 96 leaving an unfinned space equal in length to the sum of the widths of the two saws. The saws 95 and 96 operate at high speed as do the cutters 62 and 69 so that the fin adjacent to the removed fin is not bent or otherwise damaged.

The cylinders C8-C11 are adapted to have compressed air admitted into opposite ends for for moving their pistons in opposite directions. The valves V8-V11 are conventional four-way valves which are operated by their respective cam followers of the cam surfaces SS-Sll respectively, to admit air into one end of a cylinder when its respective cam follower is on its respective cam surface, and to admit air into the opposite end of the cylinder when the respective cam follower leaves its respective cam surface. The valves exhaust previously admitted air before next admitting air. The valve V12 connects the interior of the cylinder 32 to atmosphere except when the valve V12 is operated to admit compressed air into the cylinder 32.

Operation In operation, a finned tube emerging from the firming machine 10 passes through the tongs T1-T7 which close about the finned tube as it passes successively through them; the finned tube is cut-off by the saw 34; the cam cylinder is rotated backwardly to restore it to its initial position; the tongs open, and the cut-off tube drops from the tongs.

As the cut-off tube drops from the open tongs, it, guided by the guides 39, 40 and 41, falls into the open clamp between the separated clamp segments 42 and 43, .and onto the tables 44 and 45. The cam cylinder 26 again rotates forwardly as a new length of finned tube is supplied by the finning machine. Before the advancing end of the new length of finned tubing reaches the first of the tongs T1, the cam surface S8 operates the valve V8, admitting compressed air into one end of the cylinder C8, the piston of which closes the clamp segments 42 and 43 about the cut-off tube to hold it in clamped position.

Next, the cam surface S9 operates the valve V9 to admit compressed air into one end of the cylinder C9,

the piston of which moves the rotary saws to a position where their axes are in alignment with the axis of the clamped tube, with the two saws rotating, the saw motor 85 operating continuously.

Next, the cam surface S operates the valve V10, admitting compressed air into one end of the cylinder C10, the piston of which moves the rack 49 to rotate the gear 48 and the clamped tube through an angle of 360.

Shortly after the cam surface S10 operates the valve V10, the cam surface S11 operates the valve V11, admitting compressed air into corresponding ends of the cylinders C11 and C12. The motor 54 operates continuously, and rotates continuously, the spinning tool 60 and the fin cutters 62. The piston of the cylinder C11 advances the spinning tool 60 and the fin cutters 62 to close the left end of the rotating clamped tube, and to remove the fin from around that end of the tube. The motor 80 operates continuously to rotate continuously, the fin cutters 69 which remove the fin from around the right end of the tube, and the grooved tool 67 which remove the burrs from the inner surface of that end of the tube.

When the rack 49 has rotated the clamped tube 360, it and the clamped tube remain stationary for a short period of time during which the cam surfaces S9 and S11 leave their respective cam followers. The valve V9 is operated to admit compressed air into the opposite end of the cylinder C9 to cause its piston to move the saws 95 and 96 away from the clamped tube. At the same time, the valve V11 is operated to admit compressed air into the opposite ends of the cylinders C11 and C12, retracting the spinning tool 60, the fin cutters 62 and 69, and the grooved burr removing tool 67 from contact with the ends of the clamped tube.

Next, the cam surface S8 leaves its cam follower, operating the valve V8 to admit compressed air into the opposite end of the cylinder C8, to cause its piston to move the clamp segments 42 and 43 apart, and to cause the fingers 72 to eject the tube from the now open clamp.

Next, the cam surface S10 leaves its cam follower, operating the valve V10 to admit compresed air into the opposite end of the cylinder C10 for causing its piston to retract the rack 49.

The cut-off tube with its fin and burrs removed, and one end closed, is suitably received after ejection from the clamp, and is ready to be assembled in a multi-tube coil.

For some coils, the opposite ends of the tubes are left open for connection to headers so that for such tubes, the spinning tool 60 would not be required, and would be replaced with another burr removing tool.

What is claimed is:

1. In a machine for preparing spirally finned tubes for assembly in heat exchangers, a frame, clamping means for receiving and clamping a spirally finned tube dropped vertically from over said clamping means, said clamping means comprising a pair of side segments attached to said frame, said segments having inner surfaces formed as segments of a cylinder, means for moving one of said segments inwardly towards or outwardly away from the other of said segments, said segments being symmetrical about a common axis when said one side segment has been moved to its innermost position, means supporting said frame for rotation about said axis, a pair of tube ejector fingers, one of said fingers being located beyond one end of said clamping means, and the other of said fingers being located beyond the other end of said clamping means, said fingers having curved ends normally below said clamping means, a rod rotatably attached to said frame and attached to the other ends of said fingers, and means including means connected to said one side segment for rotating said rod for moving said curved ends of said fingers upwardly and outwardly when said one segment approaches its outermost position.

2. The invention claimed in claim 1 in which said means for rotating said rod comprises a pawl attached to said rod, and said means connected to said one side segment comprises a latch pivoted at one end to said one side segment and having at its other end .a surface for contacting said pawl.

3. The invention claimed in claim 2 in which said fingers between their ends are provided with upper surfaces which slope downwardly from said curved ends when said curved ends have been moved to their uppermost and outermost positions, for transferring by gravity from said frame, a tube ejected from said clamping means.

4. The invention claimed in claim 1 in which means is provided for rotating said frame about said axis sub stantially 360 in one direction, and for then rotating said frame about said axis substantially 360 in the opposite direction.

5. In a machine for preparing spirally finned tubes for assembly in heat exchangers, a frame, clamping means for receiving and clamping a spirally finned tube dropped vertically from over said clamping means, said clamping means comprising a pair of side segments attached to said frame, said segments having inner surfaces formed as segments of a cylinder, means for moving one of said segments inwardly towards or outwardly away from the other of said segments, said segments being symmetrical about a common axis when said one side segment has been moved to its innermost position, means supporting said frame for rotation about said axis, and means for rotating said frame about said axis from its normal tube receiving position a predetermined number of degrees in one direction and for then rotating said frame about said axis back to said normal position.

References Cited in the file of this patent UNITED STATES PATENTS 1,080,576 Overgaard Dec. 9, 1913 1,378,865 Hibbard May 24, 1921 1,424,755 Cullen Aug. 8, 1922 1,572,924 Hand Feb. 16, 1926 1,704,702 Floeter Mar. 12, 1929 1,956,999 Rupple May 1, 1934 2,188,447 Smith Jan. 30, 1940 {2,227,443 Denner Jan. 7, 1941 2,337,667 Kuelman Dec. 28, 1943 2,663,206 Whiting Dec. 22, 1953 2,803,153 Golbeck Aug. 20, 1957 2,835,372 Biddison May 20, 1958 

